Hi, On 15/02/2016 18:11, Nhu Nguyen wrote: > David mentioned that perhaps drying is a cause. I don't think that is the > case since air drying of pollen doesn't help to bypass The drying paper says that microwaves cause a lot of damage, presumably by making any water instantly boil and explode. If the pollen is already dry there is not that effect. -- David Pilling http://www.davidpilling.com/